Problem Statement:
When efficiently storing a large number of objects and needing to retrieve them by a unique, long numerical ID, it's crucial to determine the best data structure: an array or an object.
Array Option:
<code class="javascript">var a = [{id: 29938, name: 'name1'}, {id: 32994, name: 'name1'}];</code>
To locate an object in an array, a linear search is required:
<code class="javascript">function getObject(id) { for (var i=0; i < a.length; i++) { if (a[i].id == id) return a[i]; } }</code>
Object Option:
<code class="javascript">var a = {}; a[29938] = {id: 29938, name: 'name1'}; a[32994] = {id: 32994, name: 'name1'};</code>
With an object, retrieval is direct based on the ID used as the key:
<code class="javascript">function getObject(id) { return a[id]; }</code>
Analysis:
In general, arrays are slightly faster than objects for retrieving individual elements, particularly with large arrays. This is because objects have key-value pairs, which require additional lookup overhead compared to the simple indexing of arrays.
Performance Test Results (2017):
A performance test conducted in 2017 revealed that an array is notably faster than both a holey array and an object for retrieving a single object.
Sorting:
The sorting performance depends on the sorting algorithm used and the number of elements. While arrays can be sorted more efficiently than objects using built-in methods like Array.sort(), the difference may not be significant for smaller datasets.
Conclusion:
If the primary operation is retrieving a single object based on its ID, an array is generally more efficient than an object, especially for large numbers of objects. However, if sorting is a frequent requirement, the choice of data structure may require further testing and considerations.
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